JP2011125888A - Hydraulic press device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press device which is constituted of relatively inexpensive equipment and whose installation space is not made large. <P>SOLUTION: In the hydraulic press device in which in a state of holding a workpiece 50 between mutually opposing press dies 11, 12, at least one of the dies is moved by oil pressure, and a workpiece is subjected to press forming, a free motion unit 30 is provided between the lower die 12 and a base plate 13 holding the die, the free motion unit includes a plurality of actuators made to correspond to the respective parts obtained by dividing the press surface of the lower die 12 into the plurality ones, during the press forming, each actuator repeatedly changes pressing force to the loser die 2 or the pressing position to the lower die 12 in such a manner that friction resistance between the workpiece 50 and the lower die 12 is suppressed several times, and the repeated control is performed by each actuator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hydraulic press device that press-forms a workpiece by moving at least one die by hydraulic pressure in a state where the workpiece is sandwiched between mutually opposing press dies.

  When press forming a plate material or pipe material as a workpiece, buckling or cracking due to stress concentration may occur in the workpiece depending on the molding conditions. Known as press forming while avoiding such stress concentration is hydraulic forming or servo press forming. Patent Document 1 discloses a technique related to hydraulic forming.

Japanese Patent Laid-Open No. 2001-9529

However, in the hydraulic forming, there is a problem that a process for drying the liquid storage tank and the work after forming is required, and there is a problem that a large installation space for them is required in the factory. On the other hand, the servo press has a very expensive equipment price, and when it is press-molded by the servo press, there is a problem that the unit price of the product becomes high.
In view of such a problem, the present invention is to configure a press apparatus that performs press forming while avoiding stress concentration that causes buckling or cracking of a work with relatively inexpensive equipment without increasing the installation space. Let it be an issue.

The first invention of the present invention is a hydraulic press device that performs press molding of a workpiece by moving at least one die by hydraulic pressure in a state where the workpiece is sandwiched between press dies facing each other.
One or the other type is divided into a plurality of surfaces that are in contact with the workpiece, and a free motion unit is provided between the divided type and a base plate that holds the type. Each actuator is provided with a plurality of actuators corresponding to each of the divided parts, and each actuator presses or divides the divided mold so as to suppress the frictional resistance between the workpiece and the divided mold surface during the press molding. The hydraulic press device is characterized in that the pressing operation position with respect to the mold is repeatedly changed, and the repeated control is performed for each actuator.
According to the first invention, since a so-called vibration press similar to the servo press can be realized by using a hydraulic press that is relatively inexpensive and does not involve any accompanying equipment such as hydraulic forming, buckling or cracking due to stress concentration is achieved. The press molding can be performed while avoiding the above.

According to a second aspect of the present invention, at least one die is hydraulically sandwiched between the press dies while holding both open ends of the pipe-like workpieces on both outer sides of the press areas of the press dies facing each other. In a hydraulic press device that performs press molding of the workpiece,
One or the other mold is divided into a plurality of surfaces that contact the workpiece, and is provided between the divided mold and a base plate that holds the mold, and corresponds to each divided part of the divided mold. A cushion unit that consists of a plurality of actuators and presses the split mold away from the base plate;
During the press molding, the actuators repeatedly increase / decrease the pressing force against the split mold by a predetermined width so as to suppress the frictional resistance between the workpiece and the split mold surface, and the repeated control is performed for each actuator. Hydraulic pressure increase / decrease control means,
The actuator corresponding to the molding center of the workpiece maintains a constant pressure and presses the split mold, and repeatedly changes the pressing operation position of the actuator corresponding to the molding peripheral portion of the workpiece by a predetermined width. Pressing operation position control means to be performed for each actuator;
A shaft pressing means that presses between both ends corresponding to a portion with a large amount of molding by the press die among the workpieces at a timing when each actuator moves backward from the position where the divided die is pressed by the pressing operation position control means,
It is a hydraulic press apparatus provided with these.
According to the second invention, as in the first invention, it is possible to perform press molding while avoiding buckling and cracking due to stress concentration by using a general-purpose hydraulic press device, and at the same time, corresponding to a part with a large molding amount. Since both ends are pressed, the thickness of the workpiece can be prevented from being reduced and weakened with molding.

According to a third aspect of the present invention, in the second aspect, after the completion of the forming of the workpiece, the holding of both opening ends of the workpiece and the pressing by the shaft pressing means are released and the hydraulic pressure increase / decrease control means and the pressing operation position control means are used. A hydraulic press apparatus comprising a shape freezing means for holding one mold at a workpiece forming completion position for a predetermined time in a state in which each actuator is released.
According to the third invention, after the press molding is completed, the shape freezing is performed in which the workpiece is held at that position for a predetermined time, so that it is possible to prevent the workpiece from returning after the molding.

It is a front view showing one embodiment of the hydraulic press device of the present invention. It is the elements on larger scale of embodiment similar to FIG. It is a figure explaining arrangement | positioning of each actuator in the free motion unit of embodiment similar to FIG. It is a top view which shows the free motion unit of embodiment similar to FIG. FIG. 5 is a front view similar to FIG. 4. FIG. 5 is a side view similar to FIG. 4. It is explanatory drawing of the actuator of embodiment similar to FIG. It is a control block diagram of embodiment similar to FIG. 2 is an overall control flowchart of an embodiment similar to FIG. 1. It is a press control flowchart of embodiment similar to FIG. It is a core bar unit control flowchart of embodiment similar to FIG. It is a shaft pressing unit control flowchart of embodiment similar to FIG. It is a free motion control flowchart of embodiment similar to FIG. It is a time chart explaining operation | movement of embodiment similar to FIG. It is explanatory drawing which shows the use condition of the product press-molded by embodiment similar to FIG. It is a figure explaining the shape of the workpiece | work after the press molding completion of embodiment similar to FIG. It is a figure explaining the formation process of the workpiece | work of embodiment similar to FIG. It is a figure explaining the process of the press molding of embodiment similar to FIG. It is a figure which expands and demonstrates the process of the press molding of embodiment similar to FIG.

FIG. 1 shows the overall configuration of a hydraulic press apparatus according to one embodiment of the present invention, and FIG. 2 shows a partially enlarged view thereof. A pipe-like workpiece 50 is held between the upper die 11 and the lower die 12 of the known hydraulic press 10 by the cored bar units 15a and 15b on both outer sides of the press region, and the upper surface side of the pipe-like workpiece 50 is pressed. It is designed to be molded. The core bar units 15a and 15b are respectively inserted into both end portions so that the end portions thereof hold the both end shapes of the pipe material. Axial pressing units 16a and 16b are provided on the upper side of the cored bar units 15a and 15b. The shaft pressing units 16a and 16b are configured to press the pipe material on the molding side, that is, between both ends on the upper mold 11 side so as to reduce the length thereof, in order to prevent the workpiece 50 from being thinned due to press molding. Has been. The core bar units 15a and 15b and the shaft pressing units 16a and 16b are provided close to each other, and the shaft pressing units 16a and 16b are arranged at both ends of the workpiece 50 so as not to interfere with the tip ends of the core bar units 15a and 15b. Only the portion corresponding to the plate thickness is pressed.
In this case, the molded product is an automobile rear wheel support beam 61 as shown in FIG. 15, and the central portion of the pipe is pressed into a beam having a substantially V-shaped cross section. For this reason, the upper mold 11 is a male mold having a V-shaped cross section so as to mold the inner surface side of the V-shaped beam, and the lower mold 12 is a V-shaped cross section so as to mold the outer surface side of the V-shaped beam. It is a female type. In FIG. 15, 62 is a trailing arm, 63 is a hub, and 64 is a wheel.

2-7, the lower mold | type 12 is supported by the upper baseplate 13, and the free motion unit 30 which consists of eight actuators 30a-30h is combined with the upper baseplate 13, and each actuator of the free motion unit 30 is combined. The rods 30a to 30h are configured to pass through the upper base plate 13 and press the lower mold 12. The free motion unit 30 is supported by the lower base plate 14. A spacer 19 is disposed between the upper base plate 13 and the lower base plate 14.
Here, as shown in FIG. 4, the lower mold 12 is divided into a plurality (three in FIG. 4) 12 a to 12 c corresponding to a plurality of parts of the workpiece 50, and each actuator of the free motion unit 30. The pressing force applied to each part of the workpiece 50 under the pressing force of 30a to 30h can be made different. The idea of dividing the lower mold 12, that is, the idea of dividing the work 50 into a plurality of parts, is divided into a part in the work 50 where stress concentration easily occurs and a part that hardly occurs. In the case of FIG. 4, the part corresponding to the central part 12b in the lower mold 12 corresponds to a part where stress concentration due to molding hardly occurs, and both end parts 12a and 12c in the lower mold 12 are stresses associated with molding. It corresponds to the part where concentration tends to occur.

  Each actuator 30a to 30h of the free motion unit 30 includes a hydraulic cylinder 37 as shown by a representative actuator in FIG. 7, and the hydraulic cylinder 37 is driven by the hydraulic pressure supplied from the pump 32. The pump 32 is driven by a servo motor 33 and is configured to supply the hydraulic pressure of the pump 32 to a hydraulic cylinder 37 to operate the piston 31 in the cylinder and the rod 36 integral therewith. The tip of the rod 36 can be brought into contact with the lower mold 12. When the pump 32 is operated in a direction to push the lower die 12 by the servo motor 33, the hydraulic pressure is supplied to the lower cylinder 37a in FIG. 7, and the piston rod 36 further presses the lower die 12. When the hydraulic pressure is supplied to the upper cylinder 37b of FIG. 7 by the pump 32, the piston rod 36 acts to weaken the pressing force of the lower mold 12. The upper and lower cylinders 37a and 37b are connected to a reserve tank 35 via a relief valve 34. When the hydraulic pressure supply to the cylinder 37 by the pump 32 is interrupted, the hydraulic pressure of the cylinder 37 decreases with time, and the piston rod 36 Is in a state where the lower mold 12 is not pressed.

As shown in FIG. 3, the same hydraulic pressure is supplied from one pump 32c to the cylinders of the third actuator 30c and the fourth actuator 30d, and one pump is also supplied to the cylinders of the fifth actuator 30e and the sixth actuator 30f. The same hydraulic pressure is supplied from 32d. The other first, second, seventh, and eighth actuators 30a, 30b, 30g, and 30h are supplied with hydraulic pressure from independent pumps 32a, 32b, 32e, and 32f, respectively.
FIG. 8 is a control block diagram for each actuator, press ram, mandrel unit, and shaft pressing unit. The control unit 41 is connected to a touch panel 42 and press machine operation panel 18 that are arbitrarily operated, and is controlled. In addition to inputting operation signals to the unit 41, position sensors (not shown) of the actuators 30a, 30b, 30g, 30h and hydraulic sensors 38a-38c, 38e, 38g, 38h of the actuators 30a-30c, 30e, 30g, 30h From the position signals of the actuators 30a, 30b, 30g, 30h and the hydraulic signals of the actuators 30a-30c, 30e, 30g, 30h. Also, servo motors 33a to 33f corresponding to the actuators 30a to 30h, a mandrel unit driving hydraulic valve 15c, and a shaft pressing unit driving hydraulic valve 16c are connected to the output side of the control unit 41, and each control signal is transmitted. Output each. Although not shown, a press ram position signal is input to the control unit 41 from a press ram position sensor. Further, the press machine control panel 17 is connected to the control unit 41. The press machine control panel 17 controls a general-purpose press machine, and exchanges information so that the control unit 41 and the press machine control panel 17 can perform cooperative control with each other. The touch panel 42 arbitrarily sets a control time, a control position, and the like for control performed by the control unit 41 and the press machine control panel 17, and the press machine operation panel 18 is an operation panel of a general-purpose press machine. is there.

Hereinafter, the operation of the present embodiment will be described mainly based on the flowcharts of FIGS. 9 to 13 and the time chart of FIG.
When the control unit 41 is activated, the cored bar unit control is first executed in step 100 as shown in FIG. 9, and the cored bar units 15a and 15b are advanced in steps 101 to 103 in FIG. Thereafter, when it is confirmed in step 200 in FIG. 9 that the advancement of the core bar units 15a and 15b has started and a predetermined time has elapsed, press control is performed in step 300. Such a press control is performed in step 301 in FIG. 10 in which the press ram for operating the upper die 11 is raised at a high speed even when the press ram has a low hydraulic pressure by a press ram operation actuator (not shown) as shown in FIG. When the press ram moves from the dead center toward the bottom dead center and reaches 150 mm before the bottom dead center, the actuator for the press ram operation is switched to the high hydraulic speed at step 303. After that, when the press ram reaches bottom dead center, the press ram operating actuator is kept at high hydraulic pressure at step 305, and when a predetermined time (for example, 5 seconds) has passed and step 306 is affirmed, high hydraulic pressure is held at step 307. The press ram is moved toward the top dead center at a high speed. When the top ram is reached, the press ram is stopped in step 309.

FIG. 14B shows the advancement / retraction operation of the cored bar in the cored bar units 15a, 15b. When the cored bar is advanced from the retracted position slightly before the lowering operation of the press ram as described above, The distal end portion is inserted into both end portions of the pipe-like workpiece 50. Thereafter, the cored bar is held at the forward position in step 103 of FIG. 11 and is moved backward in step 105 when the press ram reaches the bottom dead center.
FIG. 14C shows the operation of the shaft pressing units 16a and 16b. When the press ram reaches 35 mm before the bottom dead center, the operation starts at step 402 in FIG. Detailed operation will be described later.
14D to 14I show the operation of the actuators 30a to 30h of the free motion unit 30. The hydraulic pressure in the cylinder 37 corresponding to the pressing force of the lower die 12 by the rod 36 is predetermined at substantially the same time as the press ram starts to descend. The hydraulic control for controlling the pressure is started in step 411 in FIG. 13, and when the press ram reaches 150 mm before the bottom dead center, the hydraulic pressure is intermittently decreased by a predetermined amount. This control is performed until 35 mm before the bottom dead center of the press ram is reached and step 412 is affirmed. During this time, the pressing force of the actuators 30a to 30h repeatedly increases and decreases intermittently, so-called stamping molding is performed. The timing of 35 mm before the bottom dead center is selected as a time when there is no longer any risk of buckling even in a part where buckling due to forming easily occurs in the workpiece. Therefore, the timing is set empirically.

  In the case of the present embodiment, the pipe-like workpiece 50 is formed as a beam 61 that supports the wheels of the vehicle with respect to the vehicle body by crushing the middle part excluding both ends in the longitudinal direction to form a V-shaped cross section. FIG. 16A shows a substantially right half of the pipe-like workpiece 50 that is shaped to be the beam 61. Here, B to E indicate cross-sectional shapes of respective portions of the beam indicated by A. FIG. 17 shows the forming process of the cross-sectional shape shown by D in FIG. 16, where A is a state before press forming, and B to E are divided into four stages in the forming process performed by stamping forming. As shown in FIGS. 17B to 17E, as the molding proceeds, portions corresponding to both shoulders of the V-shape having a large molding amount have a risk of buckling due to stress concentration, but stamping molding is performed. As a result, the buckling point is not limited to one place, and a phenomenon that spreads over a wide range occurs, so that molding can be continued without causing buckling. During this time, so-called blur forming is performed.

Step 3512 in FIG. 13 is affirmed at 35 mm before the bottom dead center of the press ram, and when stamping molding is completed, as shown in FIGS. 14D and 14E, the actuators 30c to 30f have a center in the lower mold 12. Control for keeping the pressing force on the portion 12b constant is performed in step 413. On the other hand, in step 414, as shown in FIGS. 14 to 14, when the press ram reaches 35 mm before the bottom dead center, the actuators 30a, 30b, 30g, and 30h are subjected to position control from the previous hydraulic control. Then, control is performed to intermittently lower the support positions of the rods of the actuators 30a, 30b, 30g, and 30h for the both end portions 12a and 12c in the lower mold 12 by a predetermined amount from the predetermined positions. That is, the support position of the both end portions 12a and 12c in the lower mold 12 is repeatedly set to a predetermined position or a position lower than the predetermined position. Therefore, in the state where the central portion 12b of the lower mold 12 shown in FIG. 4 is held at a constant pressure and the applied pressure to the central portion of the workpiece 50 is held, the support positions of the both ends 12a and 12c of the lower mold 12 are moved up and down. Vibrate.
At this time, when the support position by the actuators 30a, 30b, 30g, and 30h is lowered as shown in FIG. 14C, step 403 in FIG. 12 is affirmed, and in step 404, the shaft is pushed by the shaft pushing units 16a and 16b. In practice, both upper ends of the workpiece 50 are pushed in the axial direction, so that the workpiece 50 is prevented from being thinned by the movement of the material. Such molding is so-called inching molding, and is performed until the press ram reaches bottom dead center. F and G in FIG. 17 indicate the molding process of the workpiece during this period.

  When the press ram reaches the bottom dead center, both step 104 in FIG. 11 and step 405 in FIG. 12 are affirmed. In step 105, the core bars of the core bar units 15a and 15b are retracted, and in step 406, the shaft pressing unit 16a, The shaft pressing by 16b is also released and the unit is retracted. Further, step 415 in FIG. 13 is affirmed, and in steps 416 and 417, the actuators 30a to 30h also finish the pressure control and position control, and the workpiece 50 is released from the restraint from each unit. In step 305, the upper die 11 and the lower die 12 are simply pressed to freeze the shape of the workpiece 50. When the shape freezing for about 5 seconds is completed and step 306 is affirmed, the press ram returns from the bottom dead center to the top dead center in steps 307 to 309, and the molding of one workpiece 50 is completed.

FIG. 18 shows a series of movements of the upper mold 11, the cored bar units 15a and 15b, the shaft pressing units 16a and 16b, and the free motion unit 30 accompanying the above-described molding with time. Further, FIG. 19 shows the movement of only the workpiece 50, the cored bar of the cored bar units 15a and 15b, and the upper mold 11 in the molding process similar to FIG. In addition, in FIG. 19, it has shown so that the front-end | tip part of the cored bar units 15a and 15b may be inserted in the edge part of the workpiece | work 50 so that it may understand easily.
18A shows a state before the upper die 11 starts to operate, B shows a state in which the core bar units 15a and 15b are in the advanced positions, and the upper die 11 starts to descend, and C shows a state in which slumping is being performed. D indicates a state in which inching is being performed, E indicates that the formation of the workpiece 50 has been completed, and the upper die 11, the core metal units 15a and 15b, and the shaft pressing units 16a and 16b have all returned to the initial state. Indicates the state. 19A shows a state before the workpiece 50 is formed, B and C show a state in which the tip ends of the cored bar units 15a and 15b are inserted one by one into the end of the workpiece 50, and D shows the upper mold. 11 indicates a state in which the lowering operation is started, and E indicates a state in which stamping molding and inching molding are performed.
As described above, according to the above-described embodiment, the pipe-shaped workpiece 50 can be formed by adding the free motion unit 30 to a general-purpose hydraulic press apparatus and using no liquid like liquid seal molding as in the servo press. This can be done without buckling or cracking due to partial stress concentration.

The present invention is not limited to the appearance and configuration described in the above embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention. For example,
1. In the above-described embodiment, both stamping molding and inching molding are performed. However, depending on the shape and material of the workpiece, only stamping molding can be performed.
2. In the above embodiment, the stamping molding adopts the one that repeatedly changes the pressing force against the press die, but the control content that repeatedly changes the pressing position against the press die adopted in the inching molding in the above embodiment is adopted in the stamping molding. May be.
3. In the above embodiment, the example in which the free motion unit 30 is arranged on the lower mold 12 side has been described, but it may be arranged on the upper mold 11 side.
4). Although the case where the pipe-shaped workpiece 50 is formed has been described in the above embodiment, the workpiece may be a flat plate.

  The present invention can be used for hydraulic press apparatuses in general.

DESCRIPTION OF SYMBOLS 10 Hydraulic press machine 11 Upper mold | type 12 Lower mold | type 13 Upper base plate 14 Lower base plate 15a, 15b Mandrel unit 16a, 16b Axial pressing unit 30 Free motion unit 50 Workpiece

Claims (3)

In a state where a workpiece is sandwiched between press dies facing each other, at least one of the dies is moved by hydraulic pressure, and the workpiece is press-molded.
One or the other type is divided into a plurality of surfaces that are in contact with the workpiece, and a free motion unit is provided between the divided type and a base plate that holds the type. Each actuator is provided with a plurality of actuators corresponding to each of the divided parts, and each actuator presses or divides the divided mold so as to suppress the frictional resistance between the workpiece and the divided mold surface during the press molding. A hydraulic press apparatus characterized in that the pressing operation position with respect to the mold is repeatedly changed, and the repeated control is performed for each actuator. In a state where both open ends of the pipe-shaped workpiece are held on both outer sides of the press area by the press dies facing each other, the workpiece is sandwiched between the press dies, and at least one die is moved by hydraulic pressure to press the workpiece. In the hydraulic press device that performs molding,
One or the other mold is divided into a plurality of surfaces that contact the workpiece, and is provided between the divided mold and a base plate that holds the mold, and corresponds to each divided part of the divided mold. A cushion unit that consists of a plurality of actuators and presses the split mold away from the base plate;
During the press molding, the actuators repeatedly increase / decrease the pressing force on the split mold by a predetermined width so as to suppress the frictional resistance between the workpiece and the split mold surface, and the repeated control is performed for each actuator. Hydraulic pressure increase / decrease control means,
The actuator corresponding to the molding center part of the workpiece maintains a constant pressure and presses the split mold, and repeatedly changes the pressing operation position of the actuator corresponding to the molding peripheral part of the workpiece by a predetermined width. Pressing operation position control means to be performed for each actuator;
A shaft pressing means that presses between both ends corresponding to a portion with a large amount of molding by the press die among the workpieces at a timing when each actuator moves backward from the position where the divided die is pressed by the pressing operation position control means,
A hydraulic press device comprising: 3. The hydraulic press apparatus according to claim 2, wherein after forming the workpiece, holding of both open ends of the workpiece and releasing of the pressing by the shaft pressing means, and each actuator by the hydraulic pressure increase / decrease control means and the pressing operation position control means A hydraulic press apparatus comprising a shape freezing means for holding one of the molds at a workpiece forming completion position for a predetermined time in a state in which the pressure is released.

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